Wellington-Halton Hills MP Michael Chong recently announced the government will provide $755,000 towards the $855,000 project to restore a woolen mill that operated from 1867 to 1925.
The Grand River Conservation Authority and the Grand River Conservation Foundation will each contribute $50,000.
The ruins have become significantly deteriorated and public use has been restricted, a news release said.
Work to be done on the ruins includes shoring up the foundation, repointing the walls, capping the tops of the walls and other work to preserve the ruins.
The restoration work is slated to be finished by next spring.
The ruins are a focal point of the Rockwood conservation area and a significant tourism attraction, the release said. They have serve as settings for weddings and major film productions.